Spectroscopic methods provide a powerful tool for investigating the structural properties of immobilized proteins, For that purpose, there was a strong need for a hydrophobic particle that allows determination of the adsorbed protein conformation by fluorescence and circular dichroism. Among the various hydrophobic suspensions that are available, perfluoro-alkoxy fluoro carbon Teflon latex satisfies the requirements of low light absorption and scattering, As an example, preliminary results of structural changes of a proteolytic enzyme dissolved in aqueous solution and in the adsorbed state are given.